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The Astronomy Thread 
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Post Re: The Astronomy Thread
Absalom wrote:
Mjolnir wrote:
As far as I'm aware, the star itself being the cause has been ruled out. A star can only change brightness by changing size (which is far too slow) or by changing temperature (which is too slow and doesn't match spectral observations). A star that rapidly dims without major changes in its spectrum is being blocked by something in front of it.
How would my flare or black hole suggestions compare?


There is a distinct maximum brightness with only minor variations, with irregular but sharply defined dips. Small stars with strong magnetic fields can be highly variable, but it's hard to see how such activity would just intermittently dim the star, and do so by such large amounts. A black hole would cause a very smooth and uniform variation, and a large amount of material orbiting the black hole would form an accretion disk with its own obvious emissions.

It seems pretty certain that this is mundane matter of some form occluding the star, it's just the specific form of that matter that is rather baffling. Too cold for a dust disk, too irregular for planets, far too much of it for it to be comets...


Tue Aug 15, 2017 8:40 pm
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Post Re: The Astronomy Thread
Mjolnir wrote:
Absalom wrote:
Mjolnir wrote:
As far as I'm aware, the star itself being the cause has been ruled out. A star can only change brightness by changing size (which is far too slow) or by changing temperature (which is too slow and doesn't match spectral observations). A star that rapidly dims without major changes in its spectrum is being blocked by something in front of it.
How would my flare or black hole suggestions compare?


There is a distinct maximum brightness with only minor variations, with irregular but sharply defined dips. Small stars with strong magnetic fields can be highly variable, but it's hard to see how such activity would just intermittently dim the star, and do so by such large amounts. A black hole would cause a very smooth and uniform variation, and a large amount of material orbiting the black hole would form an accretion disk with its own obvious emissions.

It seems pretty certain that this is mundane matter of some form occluding the star, it's just the specific form of that matter that is rather baffling. Too cold for a dust disk, too irregular for planets, far too much of it for it to be comets...
If "far too much" is the best argument against comets, then I'd say the continuum between that and your "orbital snowstorm" is the best contender... at least in this thread. Haven't looked into it elsewhere, after all.


Sat Aug 19, 2017 8:22 pm
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Post Re: The Astronomy Thread
hi hi

In other interesting news. Radio telescopes have detected a repeating Fast Radio Burst source.
Galaxy sends out 15 high energy radio bursts


Wed Aug 30, 2017 6:03 pm
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Post Re: The Astronomy Thread
hi hi

This one's been big news in the science community: Colliding Neutron Stars Detected, Support Predictions as Source of Heavy Metals


Tue Oct 17, 2017 11:05 am
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Post Re: The Astronomy Thread
Haumea appears to have a ring.


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Tue Oct 17, 2017 11:37 am
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Post Re: The Astronomy Thread
hi hi

Ross 128 has a planet in the habitable zone.

The nice thing about Ross 128 is that, while it is a red dwarf, it doesn't have all the awful flares.


Wed Nov 15, 2017 3:43 pm
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Post Re: The Astronomy Thread
The viability of habitable plants around red dwarfs is a huge question, since red dwarfs make up such a huge majority of stars in our galaxy.


Thu Nov 16, 2017 8:00 am
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